i have a 91 Honda civic dx.the thermostat jumps to hot when i hit the brakes.the system isn't leaking coolant at all and res is normal.it also sits high when im in second gear until i give it gas then it returns to normal.fans work properly and i get heat.i have bled the coolant system from the bleeder valve and all air bubbles are out.replaced the coolant temp sensor,t-stat,radiator,all hoses and clamps.also when i start to accelerate the car sputters then takes off like i floored it.trannie shifts smooth and i have no leaks,fluid is at proper levels.just replaced the fuel filter and when i put additives in the fuel tank she runs like a dream.also just did a four day 1300 mile road trip through the mountains and she did fine.dont know if i should replace the fuel injectors as i think they are the originals.can they be taken out and cleaned or would i be better off getting new ones.i have a singleincome family and prefer to do things myself when possible.any insight would be helpful.

 

Look in the radiator (when cold) and make sure it is full to the top. Don't just check the reservoir.

Gauge going up immediately when you press the brakes suggests it may be an electrical problem. Warm up the engine then stop it, then turn the key back on so the guage goes up to where it was. See if the gauge moves when you press the brake pedal. Then you would know it isn't really heat doing it.

I assume you have a DPFI system with two injectors in the throttle body. They can be taken out and cleaned. Be sure to put them back the same places, as they are different (I think the brown one is on top but I'd have to go out and look at my car to be sure.) Injectors typically last the life of the car and don't require periodic replacement.